99 PLC SCADA Interview Question and Answers 2

99 PLC SCADA Interview Question and Answers 

split my one T/C signal to two separate instruments?
No. The T/C signal is a very low- level millivolt signal, and
should only be connected to the device. Splitting to two devices may result in
bad readings or loss of signal. The is to use a “ dual” T/C probe, or convert
one T/C output to a 4-20 mA signal by using a transmitter or signal
conditioner, then the new signal can be sent can be sent more than one
are the flow measuring instruments used in flow measurement?
Ø    Different pressure meters
Ø    Positive displacement
Ø    Velocity meters

working of differential pressure measurement ?
Suitable restriction placed in
flow stream causes a different pressure across it. As flow depends upon
different pressure (Head) & area so any of them or both can be varied for
varying flow.
are the components of different flow sensor?
For creating different pressure: Orifice plate, Venturi Tube, flow
Nozzle, pitot tube For measuring pressure: U- Tube Manometers, Ring- Balance
Manometer, P. Cell
type of pressure sensors used in pressure measurement?
Ø  Manometers
Ø  Bourdon tubes
Ø  Bellow elements
Ø  Diaphragm elements
Ø  DP transmitters
working of different pressure transmitters.
 Process pressure is
transmitted through isolating diaphragms and oil fill fluid to a sensing
diaphragm. The sensing diaphragm is a stretched spring element that deflects in
response to differential pressure across it. The displacement of the sensing
diaphragm, a maximum deflection f 0.004 inch (0.10mm), is proportional to the
applied pressure, Capacitor plates on both sides of the sensing diaphragm
detect the position of the diaphragm. The transmitter electronics convert the
different capacitance between the sensing diaphragm and the capacitor plates
into a two- wire mA signal and a digital output signal.
27.      What is Control
The control valve, commonly named the final control element of
control contains a pneumatic device that converts the control signal from the
controller in action, regulation the flow.
28.      What type of control
valves used in the industry?
Ø  ON – OFF SERVICES:- Gate, Ball,
Diaphragm, Plug, Butterfly valves.
Butterfly, Diaphragm, Pinch valves.
29.      What are
specifications of the control valve?
Following specifications are used for control valve
Ø  Flow medium and operating
Ø  Flow rate kg/hr or Nm3/hr                  Max/Min/Normal
Ø  Inlet and Outlet pressure :
kg/cm2       Max/Min/Normal
Ø  Max. allowable diff. Pressure :
Ø  Density of medium : kg/m3
Ø  Viscosity
Ø  Cv: Valve Flow Coefficient
30.      What are the
components of control valve?
Ø  Actuator, Body, Trim, Diaphragm,
Diaphragm plate, Actuator stem
Ø  Actuator spring, Seat, Travel
Indicator, Valve stem, Gaskets, Yoke, Hand wheel
31.      What is flow
It is the flow of water (G=1, T=6 to 34 deg. C) through the valve at
full lift in U.S. gallon per minute with a pressure drop across the valve of 1

Supervisory Control and Data Acquisition
Software : Wonderware In Touch

32.      What is SCADA ? Role
of MMI/HMI/SCADA in Industrial Automation
SCADA : Supervisory control and data acquisition
MMI : Man Machine Interface
HMI : Human machine Interface
This acts as an operator station. The operator can monitor as well
as control the process parameters from this stations. Apart from online process
data the operator will have access to historical and real-time trends, alarms
and reports. The operator can give commands to control hardware for opening the
valve, change the set point, start the pump etc.
33.      What are Features of
SCADA software?
 The common features of
SCADA include Dynamic process mimic, Tends, alarm, Connectivity with hardware,
Recipe management etc.
34.      Applications of
 SCADA systems has many
applications right industrial automation, power distribution to water
35.      Some of the leading
SCADA companies
Ø  Invensys Wonder ware In Touch
Ø  Siemens WinCC (Earlier COROS)
Ø  Allen Bradley RS View (Earlier
Control View)
Ø  Intellution ifix (Earlier Fix
Ø  GE Fanuc Simplicity
36.      Types of Wonder ware
SCADA packages
No. of I/Os-
Wondeware In Touch comes is 64, 128,256,1000, and 64,000 tags package.
Runtime + Network (DRN)/ Runtime + Network (R+N) and View Node
D+R+N: With this
packers development and editing of the application is possible, Runtime
monitoring and control of the plant is possible and Networking is possible.
R+N: With this
package development and editing of the application is NOT possible, Runtime
monitoring and control of the plant is possible and Networking is possible.
Factory Focus: With this package developments and editing of the application is N
OT possible, Runtime monitoring is possible but control of the plant is NOT
possible and Networking is possible. This package is used a view node
37.      What type of
licensing patterns used in the SCADA software
Typically two types of licenses are used in the SCADA software
Ø  Dongle Key : It is a hardware
lock which can be put on the communication port of the PC.
Ø  Software Lock: Hare the software
code is the license. Typically can put the code while installation or transfer
the code from Floppy to hard- disk.
38.      Various EXE files
used in Touch Software an there role
 InTouch : It is an application manager.
Using this you can create new application. Move between various application.
View: Window
viewer. This will start Runtime application. From this you can monitor and
control the plant.
WM: WM.XE is
Window maker. This will start the development package in InTouch. Using you can
you can develop the application.
39.      Types of Window?
Replace: Automatically
closes any window (s) it intersect when it appears on the screen including
popup other replace type windows.
Overlay: Appears on
top of currently displayed window (s) and can be larger than the window (s) it
is overlaying. When an overlay window is closed, any window (s) that ware hidden
behind it will reappear. Clicking on any on any visible portion of a window
behind an overlay window will bring that window to the foreground as the active
Popup: Similar to
an overlay window except, it always stays on top of all other open windows
(even if another window is clicked) Popup window usually require a response
from the user in order to be removed.
40.      What is Symbol
Symbol Factory contains symbols which cab be readily used in the
application. The symbol is contains include various Tanks, Reactor, Pipes
Icons, and Flags.

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